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Fencer Intel
medium 5.3

CVE-2025-3262 json

Regular Expression Denial of Service (ReDoS) in huggingface/transformers

published last yr. modified 4mo ago also GHSA-489j-g2vx-39wf , PYSEC-2026-1979 , EUVD-2025-20217

cvss
5.3
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the `SETTING_RE` variable within the `transformers/commands/chat.py` file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.

Patch / fix

  • pypi transformers 4.51.0
  • huggingface huggingface/transformers 4.51.0

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-3262 updated cvss 5.3

transformers: Regular Expression Denial of Service (ReDoS) in huggingface/transformers

  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 Red Hat AI Inference Server rhaiis/vllm-cuda-rhel9, rhaiis/vllm-rocm-rhel9 Red Hat Ansible Automation Platform 2 ansible-automation-platform-24/de-minimal-rhel8, ansible-automation-platform-24/de-minimal-rhel9, ansible-automation-platform-25/de-minimal-rhel8, ansible-automation-platform-25/de-minimal-rhel9, ansible-automation-platform-24/ee-supported-rhel8, ansible-automation-platform-24/ee-supported-rhel9, +5 more Red Hat Enterprise Linux AI (RHEL AI) rhelai1/gemma-2-9b-it, rhelai1/bootc-amd-rhel9, rhelai1/bootc-intel-rhel9, rhelai1/gemma-2-9b-it-fp8, rhelai1/skills-adapter-v3, rhelai1/bootc-nvidia-rhel9, +24 more Red Hat OpenShift AI (RHOAI) rhoai/odh-mm-rest-proxy-rhel9, rhoai/odh-model-registry-rhel9, rhoai/odh-kueue-controller-rhel9, rhoai/odh-mlmd-grpc-server-rhel9, rhoai/odh-training-operator-rhel8, rhoai/odh-training-operator-rhel9, +9 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • huntr.com https://huntr.com/bounties/ecf5ccc4-39e7-4fb3-b547-14a41d31a184 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
OSV 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
pypi transformers
>=4.49.0, <4.51.0
4.51.0

Affected products

  • huggingface huggingface/transformers

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.